A new hybrid optoelectronic wavelength-division demultiplexed (WDM) architecture to extend electronic analog-to-digital conversion (ADC) performance is analyzed and simulated. Mode-locked optical pulses are amplitude-modulated by an RF signal and optically demultiplexed into a number of parallel channels. The signal in each channel is converted to an electrical signal and then passed through a simple low-pass filter. The effect of low-pass filter response, filter matching, noise due to jitter, and detector shot noise on system performance is simulated.